Waterproofing composition and method



July 26, 1938.

B. A. ANDERTON 2,124,843

WATERPROOFING COMPOSITION AND METHOD Filed June 3, 1935 INVENTOR Benam/n A. finder fa/' ATTO R N EY Patented July 26, 1 938 UNITED STATESWATERPROOFING COMPOSITION MET HOD

Benjamin A. Anderton, Grantwood, N. J., assignor to The Barrett Company,New York,

N. Y., a

corporation of New Jersey Application June 3, 1935, Serial No. 24,713

11 Claims.

This invention relates to waterproofing, and more particularly tomembrane waterproofing,

i. e., the waterproofing with layers of bitumen and fabric or felt ofthe vertical walls of buildings, particularly cellar walls, walls offountains,

swimming pools, etc.; to the formation of Waterproof built-up roofs,especially steep roofs, constituted of alternate layers of roofing feltand waterproof coating material, and to bituminous waterproofing cementswhich may be used in membrane waterproofing.

The vertical walls of fountains and swimming pools have beenwaterproofed by coating the cement or concrete walls of the pool withbituminous material such as coal-tar pitch; frequently such coating hasbeen supplemented with alternate layers of bitumen saturated felt andbi--- tuminous 'coating material, three layers of felt separated bycoating layers and having coating layers on the third felt layer andalso a coating layer between the wall and the first felt layer beingcommonly employed. Outdoor swimming pools, fountains, roofs and likestructures are subjected to a wide range of temperatures, i. e., dayand. night, summer and winter temperatures, and to the direct rays ofthe sun. A major difiiculty encountered in such waterproofing operationshas been the selection of a bituminous waterproofing material of propermelting point and plasticity or ductility to permit it to remaincoherent and intact at'the lowest temperatures encountered and over wideranges of temperature change without bleeding or running at high summertemperatures.

Bituminous pitches heretofore employed in membrane waterproofing, whensubjected to summer temperatures, particularly to the,direct sun raysduring the summer, bled and ran along the vertical and inclined walls ofthe pool rendering the waterproofing defective. The use of a highermelting point pitch, such that it would not run when subjected tomaximum summer temperatures, would result in a poor, if not totallydefective, bonding or cementing of the felt layers to the vertical wallsof the pool or fountain. Furthermore, such high melting point pitches,particularly when subjected to winter temperatures, tend to becomebrittle and hard, impairing the waterproofing and bonding prop- 0 ertiesof the pitch, especially when subjected to the stresses resulting fromcontraction and expansion of the wall or roof to which they are applied.

The defects hereinabove pointed out in connection with pitches employedin the waterproofing of swimming pools and fountains are also present inthe pitches employed in the waterproofing of the vertical walls ofbuildings, such as cellars, and inclined construction masses or utilizedin the formation of steep built-up roofs constituted of alternate layersof roofing felt and pitch coating material.

It is an object of the present invention to pro-- vide a process ofwaterproofing, and more particularly of membrane waterproofing in whicha construction mass, such as the walls of cellars, pools, fountains,etc. and inclined roo'f decks of buildings, is coated with a so-calledhot-application bituminous waterproof composition which when appliedmolten will bond firmly with wall or roof and when used with felt orwoven fabric will result in a firm bond of the bitumen saturated sheetsto each other and to the construction mass to which they are appliedthroughout the wide range of temperatures which may be encountered bythe construction mass thus waterproofed and even though the waterproofedconstruction mass is subjected to the direct rays of the sun. Otherobjects and advantages of this invention will appear from the followingdetailed description.

The accompanying drawing is a perspective view illustrating, somewhatdiagrammatically, the waterproofing of a steep roof deck or otherconstruction mass in accordance with the invention.

I have found that by mixing a coal-digestion pitch of a melting pointsuch that the pitch is flexible and not brittle throughout alltemperatures which may be encountered in use with asbestos fibres inamount not more than 15 per cent based on the weight of thecoal-digestionpitch and preferably from five (5%) to ten (10%) per centby weight, an eminently satisfactory bonding and waterproofing cementfor 3 membrane waterproofing is, produced. Preferably the pitch employedhas a softening point of at least 40 C., a-penetration at 0 C. of atleast 4 (as hereinafter explained) and is made by heating togetherbituminous coal and tar such. as coke-oven or water-gas tar or theirdistillation products to above about 270-300" C. so that the non-ashconstituents of the mixture behave substantially as a uniform blend.

A coal-digestion pitch may be produced by heating, while agitating,bituminous coal, for example, New York steam coal, Pittsburgh Seamcoking coal, or Ohio non-coking coal in intimate contact with tar, pitchor tar distillate under specific temperature conditions so that the coalis blended with the tar or tar products in which it is digested and theresultant mixture, when molten, behaves substantially as a homogeneousfiuid. The coal may be either a coking or a non-coking coal. Productscontaining, for example, from '7 per cent to' around 25 per cent of coalare satisfactory for use in the formation of membrane waterproofingcement. The proportion of coal necessary will vary, however, with theparticular type of coal employed and also with the character of thepitch, tar or tar oil which is employed.

The temperature to which the coal and tar or pitch, which may be watergas tar,coal tar or their distillation products, are heated varies withthe particular type of coal employed but in general the temperature isaround 300 C., say from about 270 C. to 340 C.

The heating period in practice will vary depending upon the quantity ofmaterial in the heating vessel, the efficiency of the stirringapparatus, the amount of heating surface, etc. For small amounts of thematerial the period of heating to raise the temperature to around 300 C.may be only a couple of hours or less; with larger amounts in batchoperation, especially where the agitation is less rapid, 8 or 10 hoursor more may be required in order to avoid overheating portions of thecharge. 4

Products especially adapted for the practice of this invention shouldcontain in general from seven (7%) to fifteen (15%) per cent up to 25per cent of coal and should have a penetration at C. of at least 4 and asoftening point of at least 40 C. Softening points and penetrations aredetermined in accordance with procedure and using standard apparatusprescribed by the. America Society for Testing Materials. Softeningpoints referred to herein are determined by the ring and ball method.Penetration is given in tenth millimeters; in the case of penetration at0 C., 200 grams are applied for 60 seconds; for penetration at 25 C.,100 grams are applied for 5 seconds; and for penetration at 46.1 C., 50grams are applied for 5 seconds.

Preferred products for the practice of this invention may have asoftening point of, say, between 40 C. and 85 C. and a penetration at 0C. of from 4 to 25 with a penetration at 25 C. of not more than 50 abovethese values.

The following examples will illustrate the general characteristics ofcoal tar pitch products suitable for the formation of membranewaterproofing cements as hereinabove described Example 1.-Into asuitable vessel were charged about 3,200 gallons (30,700 pounds) ofdehydrated coke oven tar and 5,000 pounds of pulverized bituminous coal.While the charge was agitated, the temperature was raised slowly to320-340 C. This temperature was attained in a seven hour heating period.When the material had reached the required temperature, it was permittedto cool somewhat. The final product so'obtained had the followingcharacteristics:

Softening po 62 C. Penetration at 0 C 6 Penetration at 25 C Penetrationat 46.1 C 7 Example 2.A product prepared from 85 parts of heavy watergas tar and parts of coal exhibited the following characteristics:

Softening point 83 C, Penetration at 0 C 6 Penetration at 25 CPenetration at 46.1" C 49 Example 3.--A coal-digestion pitchparticularly suitable for waterproofing the walls of a fountain withoutthe use of a felt membrane had Penetration at 46.1 C

Example 4.-Another suitable product made from coal-digestion pitch hadthe following characteristics Softening point 69 C.

Penetration at 0 C 13.5 Penetration at C 31 Penetration at 46.1 C 91 Ihave found that the addition of asbestos fibres to such coal-digestionpitch, when introduced in amount from 5 to 15 per cent by weight of thepitch, does not have a deleterious effect on the waterproofing andbinding properties of the pitch as would an inert filler such asinfusorial earth, silica, etc. I have further found that asbestos fibresgive body and strength to coal-digestion pitch and reduce the flowtendencies thereof when subjected to elevated temperatures. Furthermore,asbestos fibres are not subject to decay.

A coal-digestion pitch of a softening point of from 50 C. to 75 C., whenmixed with asbestos fibres in the proportions stated, I have found issufficiently flexible throughout conditions of use encountered to resultin an efficient waterproof construction with or without the use ofmembranes of felt or fabric. Instead of coaldigestion pitch other pitchsuch as coal tar or water gas tar pitch of a softening point from 40 C.to 75 C. may be employed, although coaldigestion pitch hereinabovedisclosed is preferred.

In waterproofing a fountain, a mixture of 93 per cent by weight ofcoal-digestion pitch of Example 3 above and 7 per cent by weight ofasbestos fibres was employed. The pitch was melted in a kettle and theasbestos fibres added to the molten pitch while agitating the same toproduce a substantially uniform mixture. This mixture,

while hot, was mopped on the vertical walls of the fountain. The coatthus applied had a glossy appearance. Upon cooling and setting of thewaterproof composition a firm bond of the pitchasbestos composition tothe walls of the fountain resulted. The waterproof construction thusproduced, in spite of the absence of felt or fabric layers, haswithstood severe summer temperatures and has resulted in a satisfactorywaterproof structure.

The coal-digestion-pitch-asbestos 'composition may be usedadvantageously in the construction of steep built-up roofs, or othervertical or steeply inclined construction masses, involving theapplication of layers of roofing felt or woven fabric such as muslinalternating with layers of the coating composition. As illustrated inthe accompanying drawing, a layer of the coal-digestionpitch-asbestos-composition l0 may be applied to a steep roof deck orother construction mass II, and alternate layers of sheet material suchas bitumen-saturated felt I! and coal-digestionpitch-asbestos-composition applied to the initial coating layer; anadditional layer of coal-digestion pitch-asbestos-composition I3 maythen be applied to the upper surface of the felt. Such roof constructionwill be firmly bonded to the roof deck and the layers thereof will befirmly bonded to each other.

Since certain changes in carrying out the above process, and certainmodifications in the article which embody the invention may be madewithout departing from its scope, it is intended that all mattercontained in the above description or shown in the accompanying drawingshall be interpreted as illustrative and not in a limiting sense.

I claim:

1. 'The membrane waterproofing process which comprises applying acoating of coal-digestion pitch of a softening point such that the pitchis flexible and ductile under service conditions throughoutalltemperatures which may be encountered in use and asbestos fibres inamount not more than fifteen 15%) per cent, based on the weight of thepitch, to a vertical or inclined construction mass to be waterproofed,applying a layer of bitumen-saturated felt to this coating and applyinga second coating of like composition to the felt.

2. The membrane waterproofing process which comprises applying in heatliquefied condition a waterproofing composition constituted of bitumenmaterial which is flexible and ductile under service conditionsthroughout all temperatures which may be encountered in use, mixed withasbestos fibres in amount not more than fifteen (15%) per cent, based onweight of bituminous material and not less than five (5%) per cent ofthe weight of the bituminous material, to a vertical or inclinedconstruction mass, applying bitumen-saturated material to the coatinglayer and applying asecond layer of coating material of like compositionto the bitumen saturated material.

3. The process of forming a steep built up roof which comprises applyingto a steep roof deck alternate layers of waterproofing composition inheat liquefied condition and bitumen saturated felt, the waterproofcomposition being constituted of bitumen which is flexible and ductileunder service conditions throughout'all temperatures which may beencountered in use and being mixed with asbestos fibres in an amount notmore than fifteen (15%) per cent, based on the weight of the bituminousmaterial and not less than five (5%) per cent of the weight of thebituminous material and the waterproofing composition being applied inheat liquefied condition.

4. The membrane waterproofing process for waterproofing the verticalwalls of swimming pools, fountains and the like, which comprises coatingthe said walls with a composition constituted of a coal-digestion pitchhaving a softening point of from 40 to 85C. and a penetration of atleast 4 at C. and from five to fifteen (15%) per cent by weight ofasbestos fibres, said composition being applied while in heat liquefiedcondition, covering said coating "layer with sheet material and causingthe said composition to set to firmly bond said sheet material with saidvertical walls.

5. The membrane waterproofing process for waterproofing vertical orsteep construction masses which comprises coating the said constructionmasses with a composition of matter comprising a product obtainable byheating together bituminous coaland a material of the group consistingof coal tar and water gas tar and their distillation products to atemperature such that the non-ash constituents of the mixture behavesubstantially as a homogeneous blend,

said product having a softening point of at least 5.

40 C. and a penetration at 0 C. of at least 4 and being admixed withasbestos fibres in amount of from 5 to 15 per cent by weight of the saidproduct, covering said coating with bitumen-saturated felt and applyinga second coating of like composition to the bitumen saturated felt.

6. A waterproof cement adapted for application in heat liquefiedcondition, comprising coaldigestion pitch having a softening point offrom 40 to 85 C. and from 57 to per cent by weight 15 of asbestosfibres.

7. A waterproof cement comprising coal digestion pitch having asoftening point of from 40 to 85 C. and a penetration of at least 4 at 0C.

and from 5 to 15 per cent by weight of asbestos 8. A bituminouswaterproof cement consisting of a coal digestion pitch having asoftening point of about 64 C., a penetration at 0 C. of about 4,

at C. of about 15, at 461 C. of about 73 and 25 from 5 to 8 percent byweight of asbestos fibres.

9. A composition of mattercomprising a product obtainable by heatingtogether bituminous coal and a material of the group consisting of coaltar and water gas tar to a temperature such .that the non-ashconstituents in the mixture behave substantially as a homogeneous blend,said product having a softening point of at least 50 0., a penetrationat 0 C. of at least 4, and containing from 5 to 15 per cent by weight ofasbestos fibres.

10. A composition of matter comprising a product obtainable by heatingbituminous coal and a member of the group consisting of water gas tar,

coke-oven tar and their distillationproducts, to

above about 300 C. so that the non-ash constituents of the mixturebehave substantially as a homogeneous blend, said product having asoftening point of at least C., a penetration at 0 C. of at least 4, andcontaining from 5 to 15 per cent 45 by weight of asbestos fibres.

11. The waterproofing process which comprises liquefying by heat acomposition constituted of a coal-digestion pitch obtainable by heatingtogether bituminous coal and tar at a temperature such that theirnon-ash constitutents behave as a substantially homogeneous blend, saidpitch having a softening point of from 40 to C.. and a penetration of atleast 4 at 0 C. admixed with from 5 to 15% asbestos fibers based on theweight of the coal-digestion pitch, applying said coal-digestionpitch-asbestos-composition in heat liquefied condition to a vertical orsteep construction mass and permitting the heat liquefied composition toset.

- BENJAMIN A. ANDERTON.

